I filed a bug over on https://bugbase.adobe.com/
BUG ID 3291790
Vote it up so we can deliver apps over 50MB to the Google Play store!
The Google Play store requires any app over 50MB to be broken into extension files. There is currently no way to package your project in Flash Pro CS6 using Google's required methods.
I can't omptimize my project below the 50MB level. It is game with over 150 MP3 audio assets.
It should be possible to point an AIR project towards SWC files installed in another location, but I have yet to see how this is done. I think the game "Machinarium" was able to do this somehow ...
Maybe you could make an application that its only function would be to copy the mp3 files in a folder inside the device, and then from your main aplicaion you could upload "externally" the arfchivos mp3